Plant tissues such as embryos can be obtained in large quantities by mechanical means, as disclosed in U.S. Pat. No. 7,427,695, for use in tissue culture. Typically, once such plant tissues are obtained, they are used immediately or within hours in tissue culture processes with or without a transformation step. When stored for later use, its competency for transformation may be reduced. Embryonic axes derived from dry seeds, for example as disclosed in U.S. Patent Application Publication No. 2008/0280361, are relatively stable upon storage, but a hydration step prior to transformation may reduce their competency for transformation.